Problem: Stephanie ate 5 slices of pie. Ishaan ate 3 slices. If Stephanie ate $\dfrac{5}{13}$ of the pie, what fraction of the pie is remaining?
If 5 slices represent $\dfrac{5}{13}$ of the pie, there must have been a total of 13 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 8 slices, which leaves 5 out of 13 slices remaining. There is $\dfrac{5}{13}$ of the pie remaining.